He served as a member of the Legislative Assembly of Alberta from 1935 to 1967 sitting with the Social Credit caucus in government.

Hartley won the three-way race with a landslide majority easily defeating United Farmers incumbent William Shield to pick up the seat for his party.

[5] The 1952 Alberta general election would see Hartley return to office with his largest popular vote to date.

He ran in a two-way race against Liberal candidate Charles Bennett who provided the strongest challenge to Hartley's seat since 1940.

He would win the largest popular vote of his career defeating two other candidates to return to his seventh term in office.